全文获取类型
| 收费全文 | 8709篇 |
| 免费 | 2508篇 |
| 国内免费 | 570篇 |
专业分类
| 电工技术 | 2203篇 |
| 综合类 | 1044篇 |
| 化学工业 | 241篇 |
| 金属工艺 | 115篇 |
| 机械仪表 | 709篇 |
| 建筑科学 | 46篇 |
| 矿业工程 | 54篇 |
| 能源动力 | 146篇 |
| 轻工业 | 34篇 |
| 水利工程 | 25篇 |
| 石油天然气 | 27篇 |
| 武器工业 | 192篇 |
| 无线电 | 613篇 |
| 一般工业技术 | 603篇 |
| 冶金工业 | 90篇 |
| 原子能技术 | 10篇 |
| 自动化技术 | 5635篇 |
出版年
| 2025年 | 41篇 |
| 2024年 | 490篇 |
| 2023年 | 403篇 |
| 2022年 | 336篇 |
| 2021年 | 401篇 |
| 2020年 | 518篇 |
| 2019年 | 606篇 |
| 2018年 | 425篇 |
| 2017年 | 488篇 |
| 2016年 | 559篇 |
| 2015年 | 456篇 |
| 2014年 | 553篇 |
| 2013年 | 799篇 |
| 2012年 | 497篇 |
| 2011年 | 547篇 |
| 2010年 | 392篇 |
| 2009年 | 451篇 |
| 2008年 | 436篇 |
| 2007年 | 484篇 |
| 2006年 | 406篇 |
| 2005年 | 349篇 |
| 2004年 | 310篇 |
| 2003年 | 256篇 |
| 2002年 | 208篇 |
| 2001年 | 236篇 |
| 2000年 | 194篇 |
| 1999年 | 169篇 |
| 1998年 | 139篇 |
| 1997年 | 137篇 |
| 1996年 | 116篇 |
| 1995年 | 87篇 |
| 1994年 | 64篇 |
| 1993年 | 52篇 |
| 1992年 | 56篇 |
| 1991年 | 47篇 |
| 1990年 | 25篇 |
| 1989年 | 12篇 |
| 1988年 | 10篇 |
| 1987年 | 4篇 |
| 1986年 | 5篇 |
| 1985年 | 2篇 |
| 1984年 | 7篇 |
| 1983年 | 3篇 |
| 1982年 | 2篇 |
| 1981年 | 2篇 |
| 1980年 | 2篇 |
| 1964年 | 1篇 |
| 1962年 | 1篇 |
| 1954年 | 1篇 |
| 1951年 | 1篇 |
排序方式： 共有10000条查询结果，搜索用时 31 毫秒
991.
In this paper, a robust controller for a three degree of freedom (3 DOF) helicopter control is proposed in presence of actuator and sensor faults. For this purpose, Interval type-2 fuzzy logic control approach (IT2FLC) and sliding mode control (SMC) technique are used to design a controller, named active fault tolerant interval type-2 Fuzzy Sliding mode controller (AFTIT2FSMC) based on non-linear adaptive observer to estimate and detect the system faults for each subsystem of the 3-DOF helicopter.The proposed control scheme allows avoiding difficult modeling, attenuating the chattering effect of the SMC, reducing the rules number of the fuzzy controller.Exponential stability of the closed loop is guaranteed by using the Lyapunov method. The simulation results show that the AFTIT2FSMC can greatly alleviate the chattering effect, providing good tracking performance, even in presence of actuator and sensor faults. 相似文献
992.
Yeong-Chan Chang 《International journal of control》2017,90(3):463-479
This paper addresses the problem of designing mixed H2/H∞ tracking control for a large class of uncertain robotic systems. Nonlinear H∞ control theory, H2 control theory and intelligent adaptive control algorithm are combined to construct a hybrid adaptive/robust H2/H∞ tracking control scheme. One adaptive neural network system is constructed to approximate the behaviour of uncertain robot dynamics, and the other adaptive control algorithm is designed to estimate the behaviour of the modelled disturbance. Moreover, a robust H∞ control algorithm is designed to attenuate the effects of the unmodelled disturbance. Only a set of algebraic matrix Riccati-like equations is required to implement the proposed mixed H2/H∞ tracking controller, and so an explicit and closed-form solution is obtained. Consequently, the mixed H2/H∞ adaptive/robust tracking controller developed here can be analytically computed and easily implemented. Finally, simulations are presented to illustrate the effectiveness of the proposed control algorithm. 相似文献
993.
It is well known that the time-varying Kalman Filter (KF) is globally exponentially stable and optimal in the sense of minimum variance under some conditions. However, nonlinear approximations such as the extended KF linearises the system about the estimated state trajectories, leading in general to loss of both global stability and optimality. Nonlinear observers tend to have strong, often global, stability properties. They are, however, often designed without optimality objectives considering the presence of unknown measurement errors and process disturbances. We study the cascade of a global nonlinear observer with the linearised KF, where the estimate from the nonlinear observer is an exogenous signal only used for generating a linearised model to the KF. It is shown that the two-stage nonlinear estimator inherits the global stability property of the nonlinear observer, and simulations indicate that local optimality properties similar to a perfectly linearised KF can be achieved. This two-stage estimator is called an eXogeneous KF (XKF). 相似文献
994.
Haitao Li 《International journal of systems science》2017,48(4):750-756
This paper deals with the problems of robust stability analysis and robust stabilisation control design for Boolean networks with disturbance inputs. The main tool used in this paper is the semi-tensor product of matrices. First, a necessary and sufficient condition is presented for the robust stability of Boolean networks based on the algebraic representation of Boolean networks with disturbance inputs. Second, the concept of one-step robust reachability is defined for Boolean control networks (BCNs) with disturbance inputs, based on which a constructive procedure is proposed for the robust stabilisation control design of BCNs. The study of an illustrative example demonstrates the effectiveness of the obtained new results. 相似文献
995.
Guoliang Wang Qingling Zhang Chunyu Yang 《International journal of systems science》2017,48(6):1226-1241
This paper is concerned with the robust stabilsation of uncertain delayed Markovian jump systems. Given a Markovian jump system with time delay and Brownian motion simultaneously, we allow the uncertainty added in the form of additive perturbations and existing in the drift and diffusion sections at the same time. A sufficient condition on the mean square stability of system in the face of such disturbances is obtained, which is similar to small-gain theorem. A kind of partially delay-dependent controller stabilising the resulting closed-loop system is firstly designed to relate to the probability distribution of delay, whose key idea is applied to construct a delayed controller with disordering phenomenon. It is seen that the existence conditions established here could be solved easily. Based on the proposed results, some applications on robust synchronisation of uncertain delayed multi-agent systems with Markovian switching are considered. It is shown that the robust synchronisation of such an uncertain multi-agent network could be achieved by a protocol that each controller being partially delay-dependent or disordering could robustly stabilise a given single Markovian jump system. As for these cases, the proposed protocols could be obtained by solving certain algebraic Riccati equations and inequalities, which also involve weighting factors and depend on the eigenvalues of the Laplacian graph. 相似文献
996.
In this paper, we propose an LMI-based design method of a decentralised variable gain robust controller for large-scale interconnected systems with mismatched uncertainties. The mismatched uncertainties under consideration are composed of the matched part and the mismatched one, and the proposed decentralised robust controller consists of a state feedback with a fixed gain and one with a variable gain tuned by parameter adjustment laws. Sufficient conditions for the existence of the proposed decentralised variable gain robust controller are given in terms of linear matrix inequalities (LMIs). Finally, a numerical example is illustrated to validate the proposed design procedure. 相似文献
997.
In this paper, two approaches, namely active disturbance rejection control (ADRC) and Lyapunov redesign, are utilised to stabilise the vibration of a boundary-controlled flexible rectangular plate in the presence of exogenous disturbances. Based on ADRC, an estimation/cancellation strategy is applied where disturbance is estimated online by an extended state observer (ESO) and cancelled by injecting the output of ESO into the feedback loop. By the Lyapunov redesign, on the other hand, the control law intended for a nominal system is redesigned by adding a (discontinuous) control component that makes the system robust to large uncertainties. Both control algorithms are designed directly based on partial differential equation model of the plate so that spillover instabilities that are a result of model truncation are avoided. The established control schemes are able to stabilise the plate vibration by actuating and sensing only along the plate boundary while accounting for the dynamical effects of Gaussian curvature integral, in-plane membrane force and actuator mass. The stability of each control approach is proven using Lyapunov analysis. The efficacy of each proposed control is illustrated by simulation results. 相似文献
998.
This paper concentrates on investigating the robust L1 output tracking control problem for the networked control systems described by Takagi–Sugeno fuzzy model with distributed delays and uncertainties. First, according to the parallel distributed compensation and Lyapunov theory, a fuzzy delay-dependent and basis-dependent Lyapunov–Krasovskii function that contributes to reducing the conservatism is constructed. Second, the L1 performance criterion guaranteeing the asymptotic stability of the corresponding tracking control system and satisfying the prescribed tracking performance is derived. Furthermore, the output tracking control problem is converted into a convex optimisation problem. Finally, the results from simulation certify the effectiveness of the designed controller. 相似文献
999.
Hyoin Bae 《Advanced Robotics》2017,31(13):695-705
In this research, a new state estimator based on moving horizon estimation theory is suggested for the humanoid robot state estimation. So far, there are almost no studies on the moving horizon estimator (MHE)-based humanoid state estimator. Instead, a large number of humanoid state estimators based on the Kalman filter (KF) have been proposed. However, such estimators cannot guarantee optimality when the system model is nonlinear or when there is a non-Gaussian modeling error. In addition, with KF, it is difficult to incorporate inequality constraints. Since a humanoid is a complex system, its mathematical model is normally nonlinear, and is limited in its ability to characterize the system accurately. Therefore, KF-based humanoid state estimation has unavoidable limitations. To overcome these limitations, we propose a new approach to humanoid state estimation by using a MHE. It can accommodate not only nonlinear systems and constraints, but also it can partially cope with non-Gaussian modeling error. The proposed estimator framework facilitates the use of a simple model, even in the presence of a large modeling error. In addition, it can estimate the humanoid state more accurately than a KF-based estimator. The performance of the proposed approach was verified experimentally. 相似文献
1000.
Production planning of final assembly systems is a challenging task, as the often fluctuating order volumes require flexible solutions. Besides, the calculated plans need to be robust against the process-level disturbances and stochastic nature of some parameters like manual processing times or machine availability. In the paper, a simulation-based optimisation method is proposed that utilises lower level shop floor data to calculate robust production plans for final assembly lines of a flexible, multi-stage production system. In order to minimise the idle times when executing the plans, the capacity control that specifies the proper operator–task assignments is also determined. The analysed multi-stage system is operated with a pull strategy, which means that the production at the final assembly lines generates demands for the preceding stages providing the assembled components. In order to guarantee the feasibility of the plans calculated for the final assembly lines, a decomposition approach is proposed to optimise the production plan of preceding stages. By this way, the robust production can be ensured resulting in reduced losses and overall production costs even though the system is exposed to changes and disturbances. 相似文献